The mechanisms by which various enzymes catalyze reactions involving molecular oxygen are being explored. Specific enzymes under investigation are: p-hydroxyphenylpyruvate oxygenase, galactose oxidase, and inositol oxygenase. In addition, chemical model reactions for some dioxygenases are under study. BIBLIOGRAPHIC REFERENCES: R.E. Keay and G.A. Hamilton, The Epoxidation of Alkenes and the Hydroxylation of Phenols by an Intermediate in the Reaction of Ozone with Alkynes. Possible Model Reactions for Some Flavin-Containing Monoxygenases, J. Amer. Chem. Soc., 97, 6876 (1975). G.R. Dyrkacz, R.D. Libby and G.A. Hamilton, Trivalent Copper as a Probable Intermediate in the Reaction Catalyzed by Galactose Oxidase, J. Amer. Chem. Soc., 98, 626 (1976).